Spring



CLARENCE A. BROCK, 0F DETROIT, MICHIGAN.

SPRING.

speamcation of Lettersratent. V Patented l une 7, 1192i.

Application led February 5, 1917. Serial No.- 146,605.

To all 'whomI it may concern -Be it known that I, CLARENCE A. BROCK, a citizen of the United States, residin at Detroit, in the countyrof Wayne and tate of Michigan, have invented a new and useful Improvement in Springs, of which the following, together with the accompanying drawings, is a specification.

The present invention relates to the construction of springs, and particularly has reference to leaf springs such as are used on automobiles and other vehicles to support the bodies thereof above the axles. The invention resides in a construction which is readily applicable to the various types of springs at present in common use, such as semi elliptic, three quarters elliptic, full elliptic and cantaliver springs, and at the same time presents numerous advantages, as regards cheapness and ease of manufacture, over the leaf springs now in ordinary use. lt is to be understood that, for the purpose of simplifying the description, lI have shown my invention only in its application to semi-elliptic and cantaliver springs; however, it is obvious that the principle underlying my improvement is applicable to all types of leaf springs now in ordinary use.

In the manufacture of the ordinary type of leaf spring, as for instance a semi-elliptic automobile spring, a plurality of plates, each shorter than the preceding plate, are assembled upon a main or back plate, the

I latter usually providing an eye at each end for attachment to the shackles. This back plate is usually thicker than the other lates, because it must takeI endwise and si ewise shock, and oftentimes the plates are aded in thickness throughout, becoming t inner as they become shorter. Since the thicker plate or plates cannot be bent as sharply under load as the thinner ones, the ends only of all the plates are given bearing on the surface of the adjacent longer plate, that is, the plates of different lengths are formed with different ilnitial ourvaitures, so 'that these plates, when superposed one on the other but before being clamped together, are spaced apart at their central portions. When bolted together to form a spring, the shorter plates are therefore straightened out and are put under an initial strain. On the other hand, the back plate is strained negatively, that is, so that some load has to be applied to the spring before the back is straightened out to its no-load, unclamped, free state. Therefore, the highly stralned shorter plates will break first under undue load; the back, however, is safe The springs made as above described must either have a center bolt, or else nibs `must be punched therein at the center to prevent slipplng, Cllps must be provided to prevent liftmg of the ends of the shorter leaves on rebound of the spring. To prevent side movement, some expedient, such as forming lips on the sides 'of a leaf to embrace the edges of the adjacent leaf, must be resorted -to. rlhe necessity for the above operations,

in addition to the necessit for forming each plate separately with a different curvature from every other plate, makes the manufacture .of springs of this'type exceedingly expensive and tedious; since the plates must be tempered, they necessarily become `somewhat warped and invariably, when fitted together, they must be peened and hammered into place. This operation always im airs the fatigue-resistance of the spring. bviously, if all the plates could be made'over each other, of the same curvature, the diiliculties of manufacture and the expense of many of the above operations could be larlgely avoided.

he present invention contemplates the use of plates or leaves which can be laid one over the other, each running the full length of the spring. Essentially it consists of a spring whose plates or leaves are made the, maximum width at the center, and tapering toward their ends, as hereinafter fully described, reference being had in this connec-v tion to the accompanying drawings, in which- Figure 1 is a top plan view of a spring embodying the principles of my invention.

Fig. 2 is a side view of the spring, showing the same' in the position which it assumes under load.

Fig. 3 is a cross sectional view, showing one form of shackle.

Figs. 4 and 5 are views illustrating the same form of shackle, parts being broken away to disclose theconstruction.

Fig. 6 is a view in side -eleyation showing a specific application of my invention to the cantaliver type of spring, and

Fig. 7 is a fragmentary sectional view disclosing a modification in the manner of attaching the spring leaves to the shackles.

iio

, Similar reference characters refer to similar parts in the did'erent figures.

Referring particularly to Figs. l and 2, l, l indicate the plates, the same being olf maximum Width midway of their lengths, and tapering; tovvard their ends, as shown. The spring is shown in Fig. under load; obviously, in its no-load positionthe plates l assume their natural curvature `7which is imparted to them in the forming operation. The plates l, l being of the same length, and all having the same curvature, they can be formed one uponv the other, simply by thinning; them slightly toward their ends, as shown; when thus thinned, the under surface of one plate has the same curvature as the top surface of the plate directly beneath it.

ln the form shovvn in Figs. 3, l and 5, 'each plate has a spherical enlargement 2 at each end, which may be forged, Welded or otherwise formed thereon., These enlargements are adapted to seat in correspondingly shaped recesses olf the shackles 3, 3, and because of the bearing space required by each enlargement, it becomes desirable to dispose them in staggered relation Within the shackle in order to bring; the leaves or plates l, l suiliciently close together. To this end each alternate leaf is disposed with its longitudinal axis at an angle With the axes of the other leaves, as clearly shown in Fig. Vl, all of these axes intersecting at the center of the spring. To accommodate the spherical enlargements 2, each shackle 3 is preferably made in sections. central section d pro-vides hemisoherical recesses onI each side in staggered relation,l and preferably has lubricant passagevvays 5, 5, communicating With said recessesD Outer secn tions t3, 6 are provided with hemispherical recesses which match up with the recesses of the section 4f on each side to rovidebearings for the ends 2 of the spring plates, as shown, the Vparts being assembled in place and afterward the sectioned, Il and 6, t being fastened together by bolts 7, l at their ends, to form the shackle.. The inner face of the shackle thus formed is suitably recessed as at 8, 8 to permit of free and unobstructed movement of the spring leaves on the bearings provided by their ends.

With the ends of the leaves l, l thus secured for the necessary movement in the shackle or shackles, it will be seen that a semi-elliptic spring isl thereby formed, which may have, at its center, the usual seat 9 through which all of the leaves pass, the leaves at this point being separated, if desired, by fillers 9. lThe length of seating surface is very much reduced, in comparison to springs of ordinary construction, Where long seats render a considerable length of the spring ineffective. A spring of the form shown in Figs l and 2 does not need a long nascere seat, since the central section thereof, WhereY the seating is disposed, is neit weakened by the presence of any center bolt such as is used in the ordinary type of leaf spring.

Accordingl to the invention as herein d1s- 7 closed, the spring is made up of one or more leaves or plates, the cross section of each leaf or plate varyingr along?, the Whole length thereof in such a manner that the strength at any given section is approximately in proportion to the load stress on the spring; at such section. ln thisl manner the strength of the Whole spring,- is distributed evenly throughout its length with respect to the load which it is to sustain..7

bviously, a springhaving the foregoing characteristics and made with leaves or plates l, l, all of the same length but of varyingcross section, may be embodied not only in the semi-.elliptic form herein shown 8 by Way of illustration, but also in all the other forms of leaf springs now in common use, such as quarter-elliptic,threaquarters elliptic, full elliptic, cantalvcr and platform. rlhe disposition of the leaves or 9 plates in such form and the arrangement of parts, such as shackles, seats and the like, to accomplish these results, is merely a matter of adapting the known expedients in the spring; making" art to the novel form and s assemblage of leaves herein described, The invention is susceptible, obviously, to various changes in the arrangement of leaves and in the manner of attaching the same to the shackles, it being clear that many modi- 1 fications with respect to these features will suggest themselves to those skilled in the art. For example, as shown in Fig. 7, the staggered arrangement of the ends of the leaves may be dispensed with, and, if de- 1 sired, the shackle 10 may be recessed at ll to receive a row of cylindrical lugs 12, either attached to or formed integral Awith the ends of the leaves. lf desired, the recesses 1l may be in the form of elongated slots, 1 to receive the lugs 12 with freedom` for the latters movement therein, thus compensatting forl any inequality in the lengths of the leaves. After assembling, the spaces around the lugs Within the recesses may be filled up i with a bearingl metal 11.

Springs made in accordance with my invention have an important advantage in manufacture, in that all the leaves or plates are duplicates, both in size and in curva- 1.-.

ture. Furthermore, the necessity for saW- ing the leaves and for the usually practised expediente of beading, lipping, clipping and ribbing, is Wholly eliminated, since each plate is independently attached to its 1 shackle, and need not be attached to any other plate. `lin this connection, it `will be clear that the nibs, dov-wels, corx'ugations and center bolts ordinarily employed on leaf springs are Wholly dispensed with by my l l il improvements. It will be obvious also that the end thrust or shock on the spring, instead of being carried by a single leaf, is distributed between all the leaves. Moreover, in assembling the spring, it is not necessary that special provision be made for giving bearing of one leaf on another, since all the plates are the same, and are subject to the same reaction under load. In manufacturing, each plate'can be tested by itself and, in assembling, no peening, hammering or other fitting is necessary after heat treatment, such peening as is required by ordinary leaf springs being detrimental to the fatigue-resistance of the spring.

As shown in Fig. 6, a spring constituted by leaves of the conformation and arrangement hereinbefore described, lends itself readily to adaptation as a cantaliver spring, capable not only of supporting the body of ythe vehicle above the axle, but also of transmitting the impelling force of said axle to said body. Such a spring may be conveniently split or divi-ded into two parts 13 and 14, having a common point of attachment to the frame of the vehicle at the shackle 15, the leaves being held in said shackle in any suitable manner. The part 13 may be shackled or otherwise attached above the axle 16 to any member rigid therewith, such as the drum 17 used in connection with the brakes of the motor vehicle, while the part 14; may be similarly attached below the axle 16.

I claim,

l. A spring consisting of a series of superimposed leaves of equal length, with each leaf reduced in width from the center toward each end, with the ends of the leaves in different vertical planes, and a shackle uniting the ends of the leaves and ermitting a rocking movement of the end o each leaf in said shackle.

2. A spring comprising a series of superimposed leaves of equal length, with each leaf reduced in width from the center toward each end, with the ends of the leaves in different vertical planes, a shackle to which the corresponding ends of all of said leaves are pivotally attached in staggered arrangement to bring the ends of alternate leaves in the same row, and with the longiof the remaining tudinal axes of all the leaves in the same vertical plane at the center of the spring.

3. A spring comprising a plurality of superposed leaves of equal lengths, and a shackle to whichl the corresponding ends of all of said leaves are pivotally attached, the points of attachment of the leaves being staggered in arrangement to bring the ends of alternate leaves in the same row.

4. A spring I comprising a plurality of leaves of equal lengths, and means for shackling the corresponding ends of said leaves, comprising bearing lugs on the ends of said leaves, and a shackle providing staggered recesses for the reception of said bearing lugs.

5. A spring comprising a series of leaves of equal length provided at their ends with spherical lugs, a shackle uniting the ends of said leaves composed of plates placed side by side and having recesses embracing said lugs.

6. A spring comprising a series of leaves of equal length provided at their ends with spherical lugs, shackles uniting the ends of said springs composed of plates placedr side by side, with their contacting sides provided with recesses embracing said lugs, and a single lubricating channel communicating with each of said recesses.

7 A spring comprising a series of leaves of equal length having enlarged lugs at their ends, a shackle uniting the ends pf said leaves consisting of a horizontal central plate and two outer platesunited at their ends, recesses in the opposing surfaces of said plates to receive said enlarged lugs, with the recesses above said centra plate in staggered relation to the recesses below said central plate.

8. A spring comprising a series of leaves of equal length placed one above the other, with the longitudinal axes of alternate leaves placed atan angle to the longitudinal axes leaves, and with the axes of all the leaves intersecting at the center of the spring.

CLENCE A. BROCK.

Witnesses: V

ENOCH SMITH, E. J. FEFAREK. 

